1. Field of the Invention
The present invention relates to a novel outlet stopper which can be attached to a package made of a plastic bag used for containing commercial products.
2. Description of the Related Art
Commercial products which have heretofore been sold in bottles of glass or hard plastics, such as milk, soy sauce, oil, cosmetics and other like products in a fluid or slurry form, are now being sold in packages of paper cartons, bottles of thin plastic sheets and bags of plastic film (pouches).
An outlet stopper is attached to paper cartons and thin plastic bottles. A necessary amount of the content is taken out each time from the package through the outlet stopper and the remaining amount is kept in the package by closing the outlet stepper.
However, no outlet stopper is attached to plastic film bags of a pouch form. A pouch is opened by a consumer by tearing the film at a small cut made at an upper part of the pouch or by cutting an upper part of the pouch with scissors and then the contents are poured out from the package for use. When all the contents of the pouch are not used and some amount is left unused in the pouch, the opening has to be closed with a clip or the like. This causes inconvenience for the consumer.
To get rid of such inconvenience, pouches are provided with an outlet stopper. However, this practice has drawbacks in that a process of attaching a hard outlet stopper to a soft bag causes difficulty, that an outlet stepper attached to a bag causes problems in a process of packaging of commercial products by an automatic packaging machine; and that the outlet stopper causes problems in transportation and packing of bags because of its shape projected from the bag.
An outlet stopper for a packaging bag of a pouch form has been proposed recently in Japanese Patent Application Laid-Open No. 1990-127254 and Japanese Utility Model Application Laid-Open No. 1990-108872. This outlet stopper has a structure comprising a cylinder having a flange and can be attached to the surface of a pouch at the bottom of the flange with a pressure-sensitive adhesive by a consumer who has purchased the pouch. Part of the film of the pouch exposed to the inner part of the flange is then cut to open the pouch. The cylinder is closed with a cap.
The difficulty during a production process of a pouch mentioned above and, the difficulty during an automatic packaging process and the inconvenience of packing of bags can be eliminated by using an outlet stopper which can be attached tea bag by a consumer. However, this-type of outlet stopper has a drawback that additional work, such as cutting a bag and constructing an outlet stopper, are required during the operation of attaching the outlet stopper by the consumer.